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change, Then the user must specify the files 
where his knowledge descriptions are. The Natural 
Language processing module is an adaptation of 
the IDEAL system of Oliveira (1990) mentioned in 
section 1.1. It performs the queries' pragmatic- 
semantic-lexical knowledge acquisition, which is 
one of the most difficult tasks. 
  
Us 
  
  
  
poHMÜS------ --MTURAL 
i LANGUAGE 
QUERIES 
dE i REEL mme 1 
  
  
  
  
LINGUISTIC TREATHENT : 
emmy LINGUISTIC 
RNOHLEDGE 
SOURCE 
  
MODULE nl 
  
  
  
  
  
  
  
  
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LINGUISTIC ERROR ; 
REPRESENTATION | MESSAGES 
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DOKALN KNONLEDGE i 
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HODULE 3 
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fe nant ma me a a a 4 
REPRESENTATION 
PROCEDURES 
SEQUENCE 
  
  
  
Figure 1l - Environment Architecture 
The domain knowledge is represented using the 
frame model. The description of the objects 
builds up a hierarchy starting off as generic 
objects, then instances of objects and 
establishing links among them such as "a kind of" 
or "part of", see figure 2. 
After discovering the user's intention the 
linguistic module sends the semantics of the 
query to the translation module which builds up 
the program to execute the task, This program is 
constructed through the use of primitives which 
are previously defined by the user. In the 
prototype developed only 4 primitives are 
considered to some situations in the domain. 
Other situations may need the definition of new 
primitives. The defined primitives are as 
follows: 
ident - identifies the object in the domain, that 
is, checks if the object requested is part of the 
domain. 
loc - searches for the object description in the 
knowledge represented and returns all of its 
attributes, such as, location, color, width, 
size, orientation, etc. This primitive only works 
if ident has previously been activated. 
alt - performs all of the changes requested, such 
as, color, width, size, orientation alteration, 
381 
Its activation is  preceeded by primitive loc 
activation, 
  
GENERIC OBJECT 
DESCRIPTION: 
4 SIDES 
4 RNGLES 
CLASS: 2D OBJECT 
  
  
  
  
SQUARE — (INSTANCE) RECTANGLE (INSTANCE) 
DESCRIPTION: DESCRIPTION: 
4 IGUAL SIDES — (D) 2 JGUAL SIDES PAIRS (Li,L2) 
4 RIGUT ANGLES 4 RIGHT ANGLES 
ARER:- L&L. ÂRER:- LI«LE., 
PERIMETER:- 4xL. PERIHETER:- 2xLI+2=L2. 
ES L À 
  
  
  
  
  
  
  
  
object 1 ohject 2 | object 3 object 4 object 5 
in in in in in 
context context context context context 
-location -logation | | -location -location -location 
-orientat -orientat | | -orientat -orientat -orientat 
-color -color -color -color -color 
-side -side -sides -sides -sides 
  
  
  
  
  
  
  
  
  
  
  
  
Figure 2 - Frame representation of some objects 
in the domain. 
gen - creates or generates new objects in the 
context, The user defines all the object's 
attributes. 
An example of the use of these primitives can be 
found in example 1l. 
Example 1: 
User's query: 
"Mudar o quadrado da posicao x,y para w,z." 
(Change the square from location x,y to w,z). 
The transformation would result in: 
(acao:[ident,loc,alt]) (action:[ident,loc,alt]) 
(atributo: [posicao_atual: (x,y), posicao 
destino(w,z)]) 
(attribute: [original location: (x,y), 
destiny location: (w,z)]) 
(objeto : [quadrado]) (object: [square]) 
The example shows that the user specifies the 
task he wants to execute and simultaneously